Apparatus for starting discharge lamps



March 18, 1947. YOUNG ETAL 2,417,724

APPARATUS FOR STARTING DISCHARGE LAMPS I Filed July 1, 1943 w lnv e'ntrsz William RYOunQ, Prescott K.Tur-ner-,

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Patented Mar. 1947 UNITED STATES PATENT omen William R. Young and Prescott K. Turner, Fa rileld, Conn., assignors to General Electric 4 Company, a corporation oi New York Application July 1, 1943, Serial No. 493,004

a. Our invention relates to apparatus for starting discharge lamps, being a further development of the apparatus disclosed and claimed in Patent 2,274,399, February 24, 1942, and in the co'pending appl cation of Leonard W. Cook, Serial No. 470.007, filed December 24, 1942, now Patent No. 2,379,131, issued June 26, 1945, both assigned to the same ass gnee as this appication. The object ,of our present invention is to provide improved apparatus to be employed in conjunction with a lamp starter to render the starter inoperative in the event that it is unable to start the lamp.

Our invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring to the drawing, Fig. 1 is a cross sectional view of one embodiment of our invention; Fig. 2 is a perspective view of parts of said embodiment in disassembled relation; Figs. 3, 4 and 5 are detail views drawn to a larger scale; Fig. 6 illustrates a' modiflcatioh; Fig. 7 is a circuit diagram; and Fig. 8 illustrates a further modification.

As shown in Fig. 1 the starting unit I whichincludes our present invention is mounted on a part of the lamp holder 2 extending beneath the panel or reflector 3 and the lamp 4 which'it controls, the upper portion of the unit projecting through the panel into close proximity with the lamp. The starting unit comprises the base plate 8 having two projecting terminals 1 which terminals by engaging contacts in the lamp holder serve to retain the unit in place and to electrically connect it in circuit with the lamp in the common and well known manner. Secured to the base 6 in a perpendicular manner is the insulating supporting plate 9 at one side of which is mounted the capacitor ill and the lamp starting switch H which is shown by way of example as of the glow discharge tube type and on the other side of which is mounted the look-out switch l2 comprising my present invention, the two switches being connected in series between the terminals 1. The purpose of this switch is to render the starting switch inoperative after the latter has made a number of successive, unsuccessful attempts to start the lamp. The starting unit is referred to as being locked out" when the lockout switch I 2 opens to interrupt the circuit to the starting switch. Thereafter, the starting unit will not operate until the lookout switch is reset in a manner to be described later.

The two cooperating members of the lock-out switch comprise the thermal member I! and the 3 Claims. (Cl. 200-1135) 2 resilient member IS. The former is illustrated as a bimetallic strip which at one end is secured as by rivets to one face of the plate 9 and at the other end has anoifset portion forming the latch l6'.- The strip is heated by the coil ll of resistance wire, the heat produced in the coil being slowlytransmitted to the strip by the supporting strap l8 which may be soldered, welded. or otherwise secured to the strip. In its normal 10 unheated condition the latch is very close to or engages the plate 9 but when the strip is heated by the coil l'l it warps in a direction to move the latch away from the plate.

The other member i 5 of the look-out switch mayconveniently be a piece of spring wire which at one end is securely anchored to the plate 9. A simple but effective manner of anchoring the member i5 is to bend it so that it passes through the slot and the aperture 2i in the plate and 20 then to clinch or bend down the tip end firmly against the rear face of the plate. If desired, the end of the member l5 may be anchored to the plate by merely clamping it under the head 01 an eyelet l5 passing through the plate, as shown by Fig. 8. The member i5 has the intermediate loop portion 22 beyond which the member extends freely through the large opening 23 in the plate and has the end portion 24 thereof parallel with and resting against the front face of the plate.

'An important feature of our'invention is that the member I5 is anchored to the plate under tension whereby the end portion 24 is pressed against the face of the plate when restrained by the latch 24 and when not so restrained takes the position shown by the dotted lines in Fig. 3. The

tension in the member 15 is suiilcient tomaintain the end portion 24 thereof incontact with the plate notwithstanding the tendency of the latch to draw it away from the plate instead of 40 unlatching it when the bimetallic strip is heated.

In quantity production of such switches this feature is of particular value in insuring uniformity in the operation of the switches. In addition, the loop portion 22 provides greater length and hence more resilience in the member l5 and one side of the loop is in position to be engaged by the resetting button 25 which is carried and guided by the enclosing casing 26. After the switch has. opened as a result or the heating of the thermal 'member l4, ,it may be reset by pressing down the button 25 to cause the member l5 to be engaged by the latch.

In the modification illustrated by Fig. 6, member 30, corresponding with the member I! of the previously described form, is not fixed to the plate "8 9 but rather is mounted to slide thereon. That portion 24' at its upper end, as shown in Fig. 8, is arranged to slide on the front face of the plate and be held in closedcircuitposition by the latch on the member i4 just as in the previously described form. Adjoining that portion is the loop 3! which extends through the notch 33 in the plate and beyond the loop the member has the offset portion 33 which extends through the slot 34 in the plate. The spring 35 which rests against the rear face of the plate has one end attached to the plate by being passed through the aperture 38 therein; the other end extends between the plate and the offset portion 33. The spring performs two functions: one is that of lifting the member 30 to disconnect the contacts when the portion 24' is unlatched by the thermal member; the other is to hold the portion 24' against the front face of the plate with suillcient pressure to prevent it from being drawn away from the plate when the latch is withdrawn. The latter function of the spring is made possible by reason of the fact that the upper part of the offset 33 makes an acute angle with the plate and the spring wedges between the plate and that part.

What we claim as new and desire to secure by-LettersPatent of the United States is:

1. In apparatus for starting a fluorescent lamp including a starting switch, a switch for interrupting the circuit to said starting switch comprising an insulating supporting plate, a bimetallic contact strip secured at one end to said plate and having a latch at its other end, a resilient contact member carried by said plate and forming a loop intermediate its ends,'said resilient member being under tension tending to maintain one end thereof continuously in contact with said plate, and a push button arranged to engage said loop for deflecting said one end causing it to slide on said plate and to engage and be retained by said latch.

2. In apparatus for starting a fluorescent lamp including a starting switch, a switch for interrupting the circuit to said starting switch comprising a supporting plate having a slot therein. a bimetallic contact strip secured at one end to said plate and having latching means at its other end, a resilient contact member carried by said plate and having a loop formed intermediate its ends, a portion of said loop extending through said slot, and a movable operating member cooperating with the loop of the contact member to deflect one end thereof to move said end into engagement with said latching means.

3. In apparatus for starting a fluorescent lamp including a starting switch, a switch for interrupting the circuit to said starting switch comprising an insulating supporting plate, a bimetallic contact strip secured at one end to said plate and having a latch at its other end, a movable contact member carried by said plate and being formed with a loop intermediate its ends, one end 'of the member adjacent the loop being adapted to be engaged by said latch and a push button cooperating with said loop for deflecting said one end to move it into engagement with said latch.

WILLIAM R. YOUNG. PRESCOTT K. TURNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,293,897 Gref Aug. 25, 1942 2,352,940 Cook July 4, 1944 2,379,131 Cook June 26, 1945 

